Answer:
Part a) [tex]5.6\ cm[/tex] of fabric
Part b) [tex]15.9\ cm[/tex] of thread
Step-by-step explanation:
we know that
A seamstress uses [tex]5.7[/tex] centimeters of thread for every [tex]7.6[/tex]centimeters of fabric
Part a)
by proportion
Find how much fabric is involved if the seamstress uses [tex]4.2[/tex] centimeters of thread
[tex]\frac{7.6}{5.7}\frac{cm\ fabric}{cm\ thread} =\frac{x}{4.2}\frac{cm\ fabric}{cm\ thread} \\ \\x=4.2*7.6/5.7\\ \\x=5.6\ cm\ fabric[/tex]
Part b)
by proportion
Find how many centimeters of thread is needed if the seamstress is working with [tex]21.2[/tex] centimeters of fabric
[tex]\frac{7.6}{5.7}\frac{cm\ fabric}{cm\ thread} =\frac{21.2}{x}\frac{cm\ fabric}{cm\ thread} \\ \\x=5.7*21.2/7.6\\ \\x=15.9\ cm\ thread[/tex]